Telephonic receiver



July 1, 1930. F. .L EIcHMANN 1,758,630

TELEPHONIC RECEIVER Original Filed Feb. 18. 1925 VIIIIIII 4 'IIIIIIIA PatentiednJuly14 1 930 a NI -en sums Jinn-iii: Jar. nEIoinviAn-N, or -c1-iioi'iGo,{iiiLIi iois- L 1' ui'nnnr iionio I j a iic tionjaiea semen; ie25,jser1a1jn .{9,943. ,nnewea nprn as, 1929;.

My invention relates to telephonic receivers or transmitters and ini'inostpf its ask' pects relates to types of such apparatus'in which a diaphragni is separated from adjacent magnet poles by an airsp'aceand in which the appliance is adjusted by varying this air space. Generally speakinginyiinVention aims toprovide an unusually compact and inexpensive construction ofat'e'lep'honic 10 receiver or transmitter ofthis generalclass,

and also aims to provide novel magnet spool, core and permanent magne'tassemhly.

Referring to some of its more particular with respect to its support during such adjustingmoveinent. a My invention also provides a receiver or transmitter const'ruot'ion advantageously emfploying'adaminatedcore foritsfma'gnet spools, provides simple means forsecuring I each magnet spool in predetermined position with respect to the corewithout employing auxiliary 1 fastening means, and provides each mag-net core with an extension directly engaging a pole: of the permanent magnet. It also provides an assembly in which the permanent magnet, magnet spools, core and core extensions are all simu'l taneously seeured to asupporting'elemeiit, and in which such anassemb'ly can'readily be constructed in a compact form with the magnet spools" disposed between the poles of a horsesh-oefmagnet, invention'alsoprovide's si ple'meanj fe limiting the extent to which each magnet spool'core isgs'lid throughthe borel of the' correspondiiigwijre woundmagnet spool, aims't-o' provide lami- Jnated core member simple means for I wedging the cores in'the home of the 'corre- "sponding'magnet spools and utilizes the re- 7 sil encyof the-laminations for preventing "-a 5.0 loosening of the elampmgrn ans S6 .s-pect tothe diaphragm, together with means j 4 1 drawings, n WlllCZl :ceiver embodying my'inventionwith part diaphragm and the cover removed.

pears when detached; p i s Whne nthe'objects ofmyinventionmay cure; the electro-magne'ts L to the supporting element. v I V r a In "some additional objects my; invention provides" spring means for moving *the ac-1 tuating mechanism in onedire'ctionwith reoperable from outside tlie casing oi the ape pliance formoving'the mechanism 11113116 0ppo'site' direction and provides means for taking-u-p any lost motion in the said exteriorly 0" operable ad ust ng means. Furthermore my invention "provides" a convenient mounting for the wire terminals and ELIWII'G inlet adacent to these ter1n1n'als,' provides simple means for preventing the mechanism from 5 rotating so as to move thewir'e' terminals 'ou't v of-t'heir proper relation to the said nlet, and alsoprov-ides simple means for' preventing a *the spring, from contacting with-the "wire terininal'sfiStill further and also more detailed objectswillappear'from the following;

specification .and "from the accompanying Fig, 1 is an elevation'of a telephonic 'r ee of the casing broken away.

Fig. 2 isanenlar ed plan viewfoffthesainc embodiment, with-the cover of thecasing, .r

thejdiaphragm and the washer between'fthe Fig. 3' is a vertical section takenthrough j "the complete apparatus valongthe-line 3 3' of Fig. i

of the apparatus; 1

Fig. 15 is an enlarged vertical section taken along the linen- 5 of FigiZthrough one of v the wire-carrying magnet spools and its core and the adjacent parts,

Fig. 6 is an enlarged one of the 'laminated cor'e me hers as it ap; j

be embodied withequal facility in telephonic receivers and transmitters of variouet pes, my invention is particularly adaptedfojr the dense-mariner.socalled loud epeakem "as employed in connection with" radio rece ying; i apparatus. Fain therefore llustrating and is a fragmentary 'sectionftalien p Q I right" angles to Fig'iSthrough the lower part perspeetiveviewfof 'i describing it in such a connection, although I do not wish to be limited to any'particular employment of the various novel features here disclosed.

, With the illustrated embodiment positioned according to the drawings, this includesan .upwardly open and substantially cup-shaped casing having a lateral wall 1 provided with a wire inlet 2. Extending across the mouth of the casing is a diaphragm 3 which is held in place by a cover 4, desirably with a washer. 5 interposed between the cover and the adjacent part of the casing, to which part the cover is attached by, screws 6. The cover,

has a suitable tone outlet, here shown in the form of an upwardly extending tube 7 which is threadedso that the small end 8 of asuitable horn'may be attached to the same when the apparatus is to be used as a receiver, or so that a mouthpiece can be attachedwhen the apparatus is to be used as a transmitter.

i tends vertically through the bore of a spool 13' carrying a winding 14L of wire, and each of whichcores has at its lower end an extension 15 which has a portion disposed be tween the plunger top or mechanism-supporting element 9 and the one pole of a permanent magnet 16. This magnet is desirably o fa horseshoe formation, thereby permitting both magnet'spools to be disposed within its mouth and permitting the oppositely directed core extensions 15 to afford an unusually compact magnet, spool and core assembly. To hold the aforesaid parts of the mechanismv in'fixed position. with respect to the supporting plunger, I desirably secure the permanent magnet to the plunger top 9 by means which also clamp the two pole extensions 15 between the magnet and this plunger top, the magnet being disposed with the common medial plane of its shanks horlzontal or normally parallel to the diaphragm. lVith this in mind, I am here showing a clamping plate 17 of non-magnetic material engaging the upper edge of the permanent magnet and secured to theplunger top 9 by vertical screws 18, thereby clamping the magnet and the core members ointly to the plunger or supporting element. To prevent a tilting of the permanent magnet during such clamping, I desirably provide means such as a -raised hump 19 on the plunger underhanging the bight ofthe' permanent magnet.

Each core member of the apparatus, I

namely each of the memberscomprising one of the vertical cores 12 and the corresponding pole extension 15, is desirably composed of laminations in the form of thin strips of soft iron which are initially punched as exact duplicates, then have their proposed vertical core portions secured tightly to each other, and thereafter have a bend formed in the assembled strips at the proposed juncture of the vertical core portion and the horizontal extension portion of the core member. I also desirably permit one of the fastening elements, such as the head of the rivet 20 of Fig. 5, to project slightly beyond the adjacent fiat face of the core portion, thereby mak-, ing it easier to slide the spool upon the core with the rivet head formed wedgingly against the adjacent wall of the bore of the spool and with the opposite side of the core in flatwise engagement with the adjacent wall of the said bore. I also desirably form oppositely directed shoulders 21 near the bottom of each core portion, whereby I provide a definitely positioned stop onwhich the corresponding magnetspool bottoms and also increase the width of the attached core extension so as to increase the magnetic flux from the permanent magnet to the core. In thus assembling the laminated strips into a core member, the strip, portions composing the horizontal or core extension part will spread apart after the manner shown in Fig. 6 and their resiliency will tend to hold them somewhat separated; Consequently, this resiliency will afford an upward pressure against the adjacent magnet pole, thereby preventing an accidental loosening of the adjacent clamping screw 18 in case the apparatusis jarred.

To afford the needed circuit connections to the electro-magnet spools, I desirably mount upon the plunger top 9 a pair of wireterminal members 21, each of which is connected to a terminal ,wire of the double spooled electro-magnet and to one of the circuit wires 23 which extend into the casing through the lateral inlet 2.

lVith the parts thus arranged, it will be obvious that the entire actuating mechanism is mounted on the vertically movable plunger, so that the distance between the tips of the cores 12 and the diaphragm 3 can be adjusted by moving the plungerup and down within the casing. To effect such an adjusting movement without introducing lost motion, I interpose a spring 24 between the bottom 11 'Of the casing and the plunger top or supporting element 9, so that this spring will continuously tend to move the plunger tothe plunger and-mechanism will be low- Joe ered against the resistance ,of the spring, While a turning of the nut in the opposite direction will permit the spring to raise vthe plunger correspondingly. This permitsfthe desired adjustment to be'made' instantly in either 7 direction, Wl11l6 the action of the spring overcomes any looseness of fit in the threaded connection between the plunger stem and the nut.

To prevent the plunger from rotating bodily, I provide suitableinterengaging portions upon thecasing and the plunger, these being here shown in the form of upwardly extending pins 26 cast on the bottom of the casing and each extending slidably through thecorresponding vertical bore in the plunger top 9. The spring 24 is desirably of a bowed form with a central perforation through which the plunger stem extends, and the same pins 26 whichprevent the plunger from rotating are desirably placed close to one edge of the spring so as to prevent the spring from rotating about the plunger stem. Thus arranged,

have illustrated and described my invention the pins 26"prevent the spring from rotating into contact with the lower portions of the wire terminal members and also prevent the plunger top from'rotating so as 'tobring the Wire terminals out of proper relation to the Wire inlet of the casing. I

- In addition to afiording a simple means for adjusting the diaphragm, it will be seen from the drawings that a suitable fit between the plunger stem and the bore in which ittslides will 'revent' a tiltin of the mechanism;

thereby maintaining the tips of the cores12 parallel to the normal plane of the diaphragm throughout the adjusting movement. It will i 7 also be evidentthat the entire mechanism can be assembled upon the plunger before the latter is inserted in the casing, thereby greatly facilitating the assembly. However, while I i in an embodiment including desirable shapes of the various parts, I do not wish to be the said resiliency acting counter to the clamping means against loosening.

net ,a magnet spoolthrough the bore of which clamping means and serving to lock the the other leg of the magnet core extends and Y a fastening element extending through the portions of the strips'within the said bore for securing the strips to one another; the leg "ex .80 1 thereof in engagement with 'a'wall of the bore,

tending through the said bore having one face the fastening element projecting beyond the opposite face of the last named leg into engagement with the opposite Wallof the bore s0 ,as to Wedge this leg inthe bore, thereby holding the spool in fixed position with re'--v spectto the magnet. I

-' 3. a telephone receiver, a bi-part casing, a chaphragm having ts edges secured between the two parts of said casing, a telephone unit comprising a bar of solenoid coils, angular laminated pole pieces extending into said coils, and a permanent magnet havingits opposite poles engagingsaid laminated pole pieces in said casing having a plunger connected thereto andextending through saidcasin'g, a leaf spring disposed between said unit and said casing and having said plunger extending therethrough, said leaf spring 7 tending to force said unit against saiddiaphragm, and means for withdrawingsaid plunger through the casing againstthe action of said spring to "move' the unit away" from saiddiaphragm. Y

Signed at Chicago, Illinois, February 12th, 1925.;- I

limited to these shapes or to the details of the r 7, i construction and arrangement thus disclosed,

since many modifications might obviously be made without departing either from the spirit of my invention or from the appended claims 1 I claim as my invention 1. In a telephonic receiver, a pair of magnet spools, a pair of magnet cores of angular longitudinal section each having one leg thereof extending through one of the spools, I

each of'the cores being composed by superi I posed flat strips secured to each other in their said legs, and a magnet having'its poles re- I spectively in engagement with the other legs of the magnet cores, in combination with means for clamping the'magnet poles against portions of the superposed strips forming the last named legs being unsecured to each other and the strips having inherent resiliency T tending to space the said strip portions apart,

I the magnet core legs engaged by them, the a rRANKJQREronMAN 

